1. Field of the Invention
This invention relates to a method of integrating two different skins/webs into a contiguous decorative cover layer and, more particularly, to a method of molding marginal edges of the skins/webs into a lightweight foundation material to produce a tight, aesthetically pleasing seam at the juncture of the skins/webs. The invention also comprehends a panel product produced by the aforesaid method, which panel includes the foundation material and the skins fused therewith.
2. Background Art
One problem that has been particularly vexatious in the automobile interior trim art is that of integrating two skins/webs of dissimilar material into a contiguous layer to cover a fixed contour frame, as to produce an interior door panel. While description herein of the prior art and the inventive structure is focused primarily on automobile interiors, it should be understood that this same technology is common to the furniture and building industries, as well as others.
It is common on automobile door panels to use different skin/web materials. For example, a door panel may have a synthetic resin cover sheet over part of the exposed surface thereof and one or more ornamental fabric or board inserts, as around door handles, or the like.
A number of problems are contended with in integrating two dissimilar skins/webs into a panel. First of all, there is a tendency of the skins/webs to peel off of the underlying foundation surface to which they are attached, as by an adhesive. Another problem is that of maintaining the seam at the juncture of the two dissimilar webs tight, which is desirable for aesthetic reasons. Rarely do conventional techniques produce a seam of high enough quality that an overlying, decorative molding is not required.
One example of a prior art method for integrating dissimilar skins/webs onto a panel is disclosed in U.S. Pat. 4,779,390, to Repper. Repper preforms a groove in his foundation element and tucks the marginal, offset edges of the skins/webs into the groove. An adhesive is used to bond the backing surfaces of the skins to the foundation element.
The Repper manufacturing method, and product produced thereby, have numerous drawbacks. First of all, there is a tendency of the edges of the webs that are tucked into the grooves to escape from the grooves. If this occurs, the structure becomes unsightly. In the absence of an overlying molding, progressive separation of the webs from the foundation element inevitably results.
Another problem with the Repper technique is that it is inherently difficult with that technique to produce a tight seam. The skins/webs must be precisely cut and aligned to make certain that the offset marginal edges of the webs extend deeply into the preformed groove, but not entirely to the bottom thereof which would cause bulging and bunching up of the skin/web material.
The ineffectiveness of Repper in positively joining the skins/webs at the seam between adjacent webs is demonstrated by Repper's recommended use of a molding strip, which is shown in FIG. 9, to maintain the marginal edges in their receptive grooves. The need for the molding strip adds to the expense of manufacturing the door panel by requiring additional parts and assembly steps and assembly time.
A further drawback with the Repper structure is that it requires a very sturdy foundation element which will positively hold its shape. Repper suggests metal as one suitable material, which is undesirable from a weight standpoint particularly on automobiles. Today's automobile manufacturers place considerable emphasis on weight reduction, primarily for fuel economy.
A still further drawback with the Repper technique is that it is inherently difficult with that technique to prevent the development of bubbles and/or wrinkles in the web/skin.
Another known prior art method of producing a decorative panel with different skin/web materials is described below in the Detailed Description of the Drawings, relative to one of the Figures in this case. Briefly, that prior art method employs independently formed subassemblies, each with a different web/skin, which completed subassemblies are then joined to each other, as through the use of brackets or anchors.
This manufacturing method is deficient in that it requires three separate processes - two assembly routines for the subassemblies and then the connection thereof. The manufacturing process becomes quite complicated and inefficient with a resulting increase in manufacturing costs.
A further problem is that once the subassemblies are brought together, the skins/webs thereon tend to compress and wrinkle.